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Ulysses observations of a discrete wavepacket upstream of an interplanetary shock

Balogh, A.; Lucek, E. A.

We present a single example of a previously unidentified type of upstream wave structure, found several minutes ahead of a forward propagating, oblique interplanetary shock observed on day 6, 1992, using Ulysses magnetometer data. The wave appears as an isolated high frequency wavepacket associated with a larger scale compressive structure. In the…

Comet Hale-Bopp, Circumstellar Dust, and the Interstellar Medium

Waters, L. B. F. M.; Waelkens, C.; Malfait, K.

The infrared spectrum of comet Hale-Bopp, as observed with the Infrared Space Observatory (ISO), presents astonishing similarities with those of the dusty disks surrounding young stars. The prominent spectral features of crystalline silicates that occur in comets, have been observed in the circumstellar media of young and old stars, yet not in the…

A new look at the nature of comet Halley's LF electromagnetic waves: Giotto observations

Neubauer, Fritz M.; Tsurutani, Bruce T.; Glassmeier, Karl-Heinz +1 more

All of the comet Halley high-time resolution magnetic field data have been examined to determine the nature of the “turbulence” and its difference from that of comets Giacobini-Zinner and Grigg-Skjellerup. Although much of the wave appears unpolarized, occasionally there are intervals of clear order. We find several interesting new wave polarizati…

Solar wind velocity jumps across tangential discontinuities: ULYSSES observations and kinetic interpretation

Tsurutani, B. T.; Roth, M.; de Keyser, J. +2 more

Some tangential discontinuities (TDs) observed by the Ulysses spacecraft interface solar wind regions that differ only in their bulk velocity and magnetic field orientation; composition, density, temperature and magnetic field intensity are essentially the same in both regions. The relation between the plasma velocity jump across the TD and the ma…

Spectroscopic binary orbits from ultraviolet radial velocities. Paper 25: HD 152218

Stickland, D. J.; Lloyd, C.; Penny, L. R.

Field-aligned particle streaming in the duskside high latitude Jovian magnetosphere

Krupp, N.; Woch, J.; Dougherty, M. K. +7 more

We report on observations of magnetic field and energetic particle data from the Ulysses spacecraft (S/C) inside the Jovian high latitude duskside magnetosphere. We have combined particle data from the EPAC and the HI-SCALE detectors and find evidence for bi-directional streaming of electrons along the magnetic field lines during the entire outbou…

Comet de Vico (122P) and latitude variations of plasma phenomena

Brandt, J. C.; Snow, M.; Yi, Y. +1 more

In situ measurements by the Ulysses spacecraft have unequivocally established differences in solar wind properties at different solar latitudes for 1992 through 1996, and comets are exposed to these different environments depending on latitude. In the polar regions, a less time-varying appearance and a plasma tail orientation corresponding to a hi…

NGC 1427A - an LMC type galaxy in the Fornax cluster.

Infante, L.; Bomans, D. J.; Hilker, M. +1 more

We have discovered that the Fornax irregular galaxy NGC 1427A is in very many respects a twin of the Large Magellanic Cloud. Based on B, V, I, and Hα images, we find the following. The light of the galaxy is dominated by high surface brightness regions in the south-west that are superimposed by a half-ring of OB associations and Hii regions indica…

Hubble Space Telescope GHRS Spectroscopy of U Geminorum during Two Outbursts

Szkody, Paula; Sion, Edward M.; Cheng, Fuhua +7 more

We obtained Hubble Space Telescope Goddard High-Resolution Spectrograph medium-resolution (G160M grating) phase-resolved spectroscopic observations of the prototype dwarf nova U Geminorum during different stages of two different outbursts. The spectral wavelength ranges were centered on three different line regions: N V (1238 Å, 1242 Å), Si III (1…

Pole-To Solar Wind Density from ULYSSES Radio Measurements

Issautier, K.; Moncuquet, M.; Meyer-Vernet, N. +1 more

We present new in situ measurements of solar wind electron density as a function of heliolatitude. The data were obtained on Ulysses during its fast transit from south solar pole to north solar pole, at heliocentric distance about 1.5 AU, near the 1996 solar activity minimum. The density is measured accurately using the method of quasi-thermal noi…